Cross pointer flight instrument



fiec. 12, 1950 F. A. JENKS CROSS POINTER FLIGHT INSTRUMENT Original Filed May 26, 1943 w LV Patented Dec. 12, 1950 2,533,262 onoss POINTER ruoirr INSTRUMENT Frederic A. Jenks, Itockville Centre, N. Y., assignor to The Sperry Corporation, a corporation of Delaware Original application May 26, 1943, Serial No. 488,618. Divided and this application March 11, 1947, Serial No. 733,809

7 Claims. 1

This invention relates to cross pointer meters of the character that are particularly useful in the navigation and instrument landing of dirigible craft.

More particularly, the present application is a division of my copending application Serial No. 488,618, filed May 26, 1943 for cross pointer meters, now Patent 2,424,570, July 29, 1947.

The present invention relates to the indicating features of the meter in which the pointers or arms of the meter include light polarizing material to provide an opaque index where the pointers cross. Another feature of the invention resides in the provision of a reference for the porated. The pointers are deflected in accordance with the strength of an applied electrical signal by the Spring and coil actuatin means which functions as a spring-opposed electromagnetic motor. The signal controlling the pointers may originate in a radio navigation control system (not shown) of the character described and illustrated in United States Letters Patent No. 2,395,854 to T. M. Ferrill, Jr.

The background element 13 employed is generally similar in character to the one shown in the hereinbefore noted patent and includes thereon a horizontal reference line l6 and a vertical reference line H. Pointer E2 in connection with line index of the meter that is formed of transparent 15 i6 indicates up-down displacement of the craft or translucent material with an opaque scale fromagiven path. Also, pointer ii in connection thereon. with line ii indicates right-left displacement of Other features and structural details of the inthe craft from the path. Lines 16 and I? on elevention will be apparent from the following dement i3 provide a reference scale on which the scription when read in relation to the accorn- 20 position of the crossing portion of the two pointpanying drawing, wherein ters H and i2 is observed. As shown, the ele- Fig. 1 is a front elevation of the improved meter ment 53 may be formed in the shape of a spheriand a similar view of a conventional artificial cal segment, the pointers may be arcuately shaped horizon; and the lines I6 and H on the reference may be Fig. 2 is a vertical cross-section of the meter 25 graduated or sealed by short intersecting lines to instrument shown in Fig. 1; provide an indication of the degree of displace- Fig. 3 is an enlarged detail front view showin ment of the craft from the path. a modified form of the cross pointers; and As herein shown, the reference element i3 is Fig. 4 is a circuit diagram and schematic view mounted for pivotal movement with respect o showing the relation of the two instruments illus- 30 housing to as the craft moves or turns about its trated in Fig. 1. roll axis by means of bearings l9. To provide With reference particularly to Figs. 1, 2 and 4. stabilization of the element l3 of the meter with a cross pointer meter constructed in accordance regard to the roll axis of the craft on which the with the present invention includes a housing In meter is mounted, I employ in this instance, a for the moving parts of the instrument which are gy o ver c in the form of an a tificial horizon provided by the elongated arms or crossed pointgenerally cat d at ers I! and i2 andabackground element l3. The As illustrated in Fig. 2, element 13 may be crossed arms H and 12 are mounted so that the mounted on a reflector 20 by suitable connecting same are free to move relatively to one another in means. Reflector 20 is provided with a hollow mutually perpendicular relation as well as more so p ojecti g e d Sl ve 22 that journals in t b relatively to the reference element l3. A window ings 19 in the housing. It will be understood that 14 in front of the housing l0 permits an observer the provided axis of movement of t e element I3 to see the position of the crossed pointers relais situated in parallel or aligned relation to the tive to the element [3. A spring and coil comfore and aft axis of the craft on which the meter bination is provided to position each of the movais mounted. This axis is indicated generally at ble pointers, only the combination 15 for pointer 24, in Fig. 4. ll being generally indicated in Fig. 2 in the pres- With reference to Fig. 4, the conventional arent instance. The spring and coil combination, tificial horizon 18 may include a gimbal ring 25 which are not illustrated in detail, may be of t e whose axis 26 is parallel to axis 24. A gyro rotor character particularly shown and described in (39 bearing case 21 is mounted for pivotal movement connection with DArsonval meter illustrated in Fig. 10-1 on page 354 of volume 1 of the book by John H; Morecroft and Frederick W. Hehre entitled Electrical Circuits and Machinery published in 1933 by John Wiley and Sons, Incorin the usual manner on rin 25. As well understood in the art, if the craft banks about its ro l or fore and aft axis, movement thereof with reference to axes 26 and 24 results, and in the artificial horizon instrument I! a bank indication is provided by relative angular, displacement between the referenc 23 of the horizon and its associated stationary index 29', Fig. 1. The means provided, in the present instance, to stabilize the element I3 is the gyro vertical of the artificial horizon l8 and a self-synchronous position repeating system linking the same with the meter and including an electrical data transmitter 29 and an electrical data receiver 30. The stator 3| of the transmitter 23 is situated at the gyro vertical and the rotor 32 thereof is positioned relatively to the stator 3| by connection of the same to the gimbal ring 25. Stator 33 of the receiver 30 positioned in the housing In of the meter is connected to receive the output signal of the transmitter 29 by way of leads 34 through the amplifiers 35. Rotor 36 of the receiver 30 is connected to the sleeve 32 by a coupling 31, Fig. 2. As shown in Fig. 2, the receiver 30 is fixedly mounted in a casing 38 forming an extension at the rear of the meter instrument housing Ill. The rotors 32 and 36 of the repeating system are supplied with energy from a common source of alternating current generally indicated at 39. The electrical system shown functions as a position repeating device that stabilizes the element l3, the transmitter thereof being situated at the roll axis of the gyro vertical and the receiver thereof being situated at the axis of the element I3.

Heretofore when making instrument landings with a cross pointer meter, the sense of bank of the craft was supplied by an auxiliary instrument such as an artificial horizon or bank-turn indicator. This information had to be obtained by occasional glances at the auxiliary instrument,

thereby causing the pilots attention to be momentarily removed from the cross pointer meter. ,This requirement is distinctly disadvantageous, particularly when the craft is in the final stages of landing. With the improved meter a bank sense is obtained directly from the orientation of the element I3 in the instrument landing cross pointer meter so that it is unnecessary for the pilot to divert his attention from the single instrument at any stage in the landing of the craft. In this connection, the background element [3 of the meter provides a bank indicating reference 4|! thereon which cooperates with an index 4! located on the housing I ll of the instrument.

As shown, a further bank indication may be provided by the spaced indices 42 on the housing and by the line 16 of the element 13. If desired, the background element may be constructed in two equally sized sections of different degrees of translucency to define the bank line It thereon. The portion of the element above the line 16 may be a light amber translucent material while that below the line may be a dark amber translucent material. With illumination supplied to the element l3 from the rear, the upper portion thereof simulates the sky and the lower portion simulates the earth so that when the craft banks, the meter will apparently indicate such condition relative to the earth instead of to an artificial In the improved instrument, the cross pointers or arms H and I2 are made of light polarizing and preferably translucent material whose respective polar zing planes are arranged in mutually perpendicular relation to provide a uniformly opaque index where the arms cross readable on the reference element, as shown in Fig. 1. In the modification of the invention shown in Fig.3, the respective pointers ii and 12 are longitudinally slotted as indicated at 41. This type of polarized pointer may be employed when the cross pointer reference lines [6 and H are graduated or scaled to indicate the approximate displacement of the craft from the path.

Preferably, the rear of element l3 may be frosted to create the impression that the observer is looking into the instrument instead of looking at it. The rod 44 may be formed of a plastic material that is transparent or translucent.

Since many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departure from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. An indicating meter of the cross pointer type comprising a transparent element having an opaque reference thereon, a pair of elongated arms movable relatively to one another in mutually perpendicular relation and movable relatively to the reference element, said arms being made of light polarizing translucent material whose respective polarizing planes are arranged in mutually perpendicular relation to provide a uniformly opaque index where the arms cross readable on the reference element, and means for illuminating said element and arms.

2. A meter as claimed in claim 1, in which the element is translucent.

3. A meter as claimed in claim 1, in which the opaque reference is two mutually perpendicular lines.

4. A meter as claimed in claim 1, in which the opaque reference is two mutually perpendicular lines and the arms are slotted longitudinally.

5. In an indicating meter of the cross pointer type, a pair of elongated arms movable relatively to one another in mutually perpendicular relation, said arms being made of light polarizing material whose respective polarizing planes are arranged in mutually perpendicular relation to provide a uniformly opaque index Where the same cross, means operable to move one of said arms, and means operable to move the other of said arms.

6. In an indicating meter of the cross pointer type, a pair of elongated arms movable relatively to one another in mutually perpendicular relation, said arms being made of light polarizing material whose respective polarizing planes are arranged in mutually perpendicular relation to provide a uniformly opaque index where the same cross.

7. An indicating meter of the cross pointer type adapted to be mounted vertically on an instrument panel comprising a translucent spherical segment having references thereon, a air of arcuate arms pivoted behind said segment on normally vertical and horizontal axes and movable relatively to one another in mutually perpendicular relation and movable around the face of the spherical segment, said arms being made of light polarizing material 7 whose respective polarizing planes are arranged in substantially perpendicular relation to provide an opaque index where the arms cross readable on said references, and means or illuminating said segment and arms from behind.

FREDERIC A. JENKS.

REFERENCES CITED The following references are of record in the file of this patent:

6 UNITED STATES PATEN'I'S Numcer Number Name Date Dixon et a1. July 16, 1918 Wheelwright, 3d. June 18,1938 P'ratt July 12, 1938 Land July 11, 1939 Stickney Dec. 2, 1941 Neumueller et a1. Apr. 21, 1942 Bradley Feb. 26, 1946 Jenks July 29, 1947 FOREIGN PATENTS Country Date Germany Nov. 15, 1933 

